Phenotypic variation in biotinidase deficiency

Phenotypic variation in biotinidase deficiency

Phenotypic variation in biotinidase deficiency Biotinidase deficiency is the usual biochemical defect in biotin-responsive late-onset multiple carboxy...

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Phenotypic variation in biotinidase deficiency Biotinidase deficiency is the usual biochemical defect in biotin-responsive late-onset multiple carboxylase deficiency. We reviewed the clinical features o f six patients with the enzyme deficiency and compared them with features described in the literature in children with late-onset MCD. In all o f the reported probands, MCD was diagnosed because they had metabolic ketoacidosis and organic aciduria in addition to various neurologic and cutaneous symptoms, such as seizures, ataxia, skin rash, and alopecia. Although in several o f our patients biotinidase deficiency was also diagnosed because they manifested a similar spectrum o f findings, others never had ketoacidosis or organic aciduria. Thus the initial features o f biotinidase defieiency usually include neurologic or cutaneous symptoms, whereas organic aciduria and MCD are delayed, secondary manifestations o f the disease. These findings suggest that biotinidase deficiency should be considered in any infant or child with any o f these neurologic or cutaneous findings, with or without ketoacidosis or organic aciduria. I f the diagnosis cannot be excluded, such individuals should be given a therapeutic trial o f pharmacologic doses o f biotin. (3 PEDIATR 103:233, 1983)

Barry Wolf, M.D., Ph.D., Robert E. Grier, M.S., Richard J. Allen, M.D., Stephen I. Goodman, M.D., Craig L. Kien, M.D., Ph.D., W. Davis Parker, M.D., David M. Howell, M.D., and Daniel L. Hurst, M.D. Richmond, Va., Ann Arbor, Mich., Denver, Colo., Milwaukee, Wis.. and Aurora, Colo.

MULTIPLE CARBOXYLASE DEFICIENCY has two forms: the neonatal and the late-onset forms.' The neonatal form is characterized clinically by vomiting, lethargy, and hypotonia, and biochemically by severe metabolic ketoaci-

From the Departments o f Human Genetics and Pediatrics, Children's Medical Center, Medical College o f Virginia; Department o f Pediatrics and Neurology, Section o f Pediatric Neurology, University o f Michigan Medical Center," Department o f Pediatrics, University o f Colorado School o f Medicine; Departments o f Pediatrics and Biochemistry, Medical College o f Wisconsin, the Milwaukee Children's Hospital; and Department o f Pediatrics, Fitzsimons Army Medical Center. Supported by Grant A M 25675 from the National Institutes o f Health and Grant 6-342from the National Foundation~March o f Dimes. Dr. Wolf is the recipient o f N I H Research Career Development Award A M 00677; Mr. Grier is the recipient o f N l H Predoctoral Training Grant GM 07492. Paper 197 from the Department o f Human Genetics, Medical College o f Virginia. Reprint requests: Barry Wolf M.D., Department o f Human Genetics, Medical College o f Virginia, P.O. Box 33, M C V Station, Richmond, Va 23298.

dosis, hyperammonemia, and organic acidemia. This disorder can be described more precisely as holocarboxylase synthetase deficiency, the primary enzymatic defect in this disease? -4 The biochemical features of the late-onset form of MCD are similar to those of the neonatal form, but the clinical findings have usually included seizures, ataxia, skin rash, and alopecia? We have shown recently that this autosomal recessively inherited condition usually results from a defect in biotinidase activity. 5,6 Therefore, lateonset MCD should be designated biotinidase deficiency. See related article, p. 265.

I

MCD

Multiplecarboxylase deficiency

Biotinidase catalyzes the liberation of biotin from its covalent linkage to the E-amino lysyl group of the various carboxylases, thereby allowing the recycling and reutilization of biotin], 8 Affected individuals with either holocarboxylase synthetase or biotinidase deficiency improve clin-

The Journal o f P E D I A T R I C S

233

234

W o l f et al.

The Journal of Pediatrics August 1983

ically when administered pharmacologic doses of biotin. / W e have also encountered several patients with biotinidase deficiency who initially had neurologic and cutaneous symptoms in the absence of recognized metabolic acidosis or organic aciduria. These findings suggest that in this disorder the diminished carboxylase activities are delayed effects caused by biotin deficiency and exacerbated by the accumulation of biocytin (oN-biotinyMysine). Patients with relevant neurologic or cutaneous findings of unknown cause should therefore be evaluated for. biotinidase deficiency and treated with pharmacologic doses o f biotin before overt metabolic decompensation occurs. MATERIALS

AND METHODS

Organic acid screens were determined as described? Propionyl C o A carboxylase, /3-methylcrotonyl C o A carboxylase, and pyruvate carboxylase activities were measured in peripheral blood leukocytes and in cultured skin fibroblasts as previously described. 1~ Biotinidase activity in serum was determined colorimetrically by measuring the liberation of p - a m i n o b e n z o a t e from N-biotin-p-aminobenzoate.~ CASE REPORTS Patient 1. This 3090 gm white infant girl was the product of an uncomplicated pregnancy. Her parents were nonconsanguineous. Apgar scores were 9 and 9 at one and five minutes, respectively. At 9 weeks of age, the infant had tremors, and was admitted to the hospital for evaluation. No metabolic abnormalities were recognized, but an abnormal EEG pattern was noted; she was subsequently discharged with no specific treatment. The infant was breast-fed until 3V2 months of age. At that time she was readmitted because of continuous uncontrollable seizures that failed to respond to various anticonvulsant drugs including phenytoin, thiamine, and pyridoxine. EEG patterns continued to be abnormal, with paroxysmal burst suppression activity. Urinary excretion of amino acids and organic acid screens were normal. During the last few days of life the infant bad hyperammonemia (900 /~g/dl; control <200/zg/dl), developed lactic acidosis (12.6 mg/dl; control <3.7 mg/dl), and the diagnosis of Leigh syndreme was considered. CSF protein concentration was slightly elevated (67 mg/dl). The infant's condition deteriorated, with uncontrollable seizures and ophthalmoparesis, and she died at 4 months of age. Skin lesions, alopecia, and organic aciduria were not noted. Serum was unavailable for measurement of biotinidase activity. Patient 2. This 3400 gm female sibling of patient 1 was the breech product of an uneventful pregnancy. Apgar scores were 9 and 9 at one and five minutes, respectively. During the first three weeks of life the mother noted some jerking limb movements, which she considered to be seizure activity. Results of an EEG and repeated screening for organic acids in the urine, however, were normal. Despite these negative findings, the infant, who was breast-fed, was given a low-protein diet and anticonvulsant drugs, and showed marked neurologic improvement. At 1 year of age, she was noted to have neurosensory hearing loss, which was improved

by the use of a special hearing aid. Examinations of urine for organic acids yielded repeatedly normal findings, as did a computerized axial tomographic scan of the brain. At 2~/2years of age the child was again admitted to the hospital because of inadequate weight gain, but laboratory studies failed to reveal any specific abnormalities. It was noted, however, that her hair was thinning. Empirically, she was given 20 mg biotin daily, even though pretreatment serum biotin concentrations were reported to be normal on several occasions. With biotin treatment, the mild alopecia resolved quickly; and at 3 years of age, tO determine whether she was in fact biotin dependent, the supplemental biotin therapy was discontinued. Within two weeks she began to lose her hair, but did not develop signs of metabolic decompensation. Plasma biotin concentration at that time was 99 pg/ml (normal >200 pg/ml), and biotin supplementation was promptly resumed. Plasma biotin concentration increased to 1490 pg/ml. At 4~A years of age, the child continues to do well with biotin therapy. She has never developed seizure activity or a skin rash and has never had organic aciduria. Propionyl CoA carboxylase, pyruvate carboxylase, and fl-methylcrotonyl carboxylase activities were normal in fibroblasts cultured in medium containing 10% fetal calf serum. Biotinidase activity was undetectable in the patient's serum. Mean normal activity is 5.80 nmol/min/ml serum (range 4.30 to 7.54 nmol/min/ml serum). Patient 3. This male sibling of patients 1 and 2 was breast-fed until 6 months of age. He was well until 14 months of age, when he first manifested hair loss without neurologic symptoms. He was promptly given biotin (20 mg/day), because of his sister's history, although plasma biotin concentrations were within the normal range on two occasions prior to treatment (800 pg/ml and 150 pg/ml). He did not have organic aciduria. At 2 years of age biotin therapy was discontinued, and like his sister, he developed alopecia and began to have mild ataxia. Plasma biotin concentrations were below normal (184 pg/ml and 63 pg/ml). Biotin treatment was resumed, and plasma concentrations increased to 1665 pg/ml. At 3 years of age, he continues to do well. He never developed a skin rash or organic aciduria. Serum biotinidase activity was undetectable. Patient 4. Clinical and biochemical findings in this 5V2-year old boy have been reported elsewhere?4 His parents were not consanguineous, and he was not breast-fed. Serum biotinidase activity was 0.16 nmol/m~n/ml. Patient 5. This white infant girl was the product of an uncomplicated full-term pregnancy and delivery. The parents were not consanguineous. She was breast-fed until 10 months of age, when she began to exhibit poor fine and gross motor control, hypotonia, and ataxia. Neurologic symptoms included echolalic speech and developmental delay. A skin rash was diagnosed as seborrhe!c dermatitis; a fungal skin infection on the nape of the neck failed to respond to topical therapy. Serum zinc concentrations'were normal. Treatment with multivitamins, which did not contain biotin, had no effect on the skin rash or neurologic symptoms. At 3 years of age, a computed tomographic scan of the head revealed a right parietal cyst, which was surgically removed. After surgery, she had mild left-sided hemiparesis and questionable seizures, which were treated with phenytoin. She was also noted to

Volume 103 Number 2

Table.

Phenotypic variation in biotinidase deficiency

23 5

C o m p a r i s o n of clinical f e a t u r e s in c h i l d r e n w i t h biotinidase deficiency w i t h those o f

c h i l d r e n w i t h d o c u m e n t e d or p r o b a b l e l a t e - o n s e t m u l t i p l e c a r b o x y l a s e deficiency !

]

._

.~

~

"~,

+

-

"~.

! 1

+

9

2 3 4 5 6 7 8 9 10 11

15 28 29 30, 31 3l, 32 33

+ + + + + ? ? ? ? ?

12

33

?

14

wk

+

.

3 wk 14 mo 12 mo 10 mo 24 mo 3 mo 10 mo 6 mo 8 mo 21Amo

+ + -+ + -+ . +

+ + + + -+ -

3 mo

+

13 33 ? 3 mo 14 34 ? 7 wk 15 35 ? 3 mo 16 35 ? 6 mo 17 26 ? ? Number with feature/ number evaluated

.

.

+

.

+ + + + + + + +

--

+ + + + + + . +

+

-

+

-

-

+ + + § +

+ + + ?

+ + + + ?

+ . + + +

.

.

+ + + + + + ? ? 11/16 9/16

.

. . . + + + + .

.

.

.

. .

.

+

.

.

. + + + . .

.

. + . + .

+ + .

. .

.

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?

.

. _ _ ?

.

.

.

.

NA

---

+ +

+ + + + ?

? ? ? ? ?

+ + + + ?

+ + + + + + + + + NA

.

. • +

. + + + • 9

-

. .

. . + +

-+ .

+ -

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. .

+

.

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-

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NA

_

+

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+ + ?

+ + + + +

+ ? + + ?

• ? ? ?

+ + + + +

+ + + + +

11/15

14/14

.

12/17 12/16 8/16 7 / ! 7 4/16 2/16 2/16 5/16

13/16

11/14 3/8

Died (4 mo)

Died (8 too) Died (39 too)

NA, Not attempted.

have tachypnea and mild metabolic acidosis. The skin rash remained, and her hair, which had been shaved for surgery, failed to grow back. The ataxia and hypotonia became more pronounced. She was also noncommunicative and was found to have bilateral optic atrophy, worse in the right eye. At 389 years she was admitted to the hospital in a coma with metabolic ketoacidosis without hyperammonemia. Serum lactate concentration was about 21/2 times normal. Urifiary organic acid screen revealed elevated concentrations o f hydroxyisovaleric acid and/3-methylcrotonylglycine. Biotin treatment was begun (20 mg twice a day for three days and then 10 mg twice a day). Urinary organic acid excretion was normal by the }bird day of therapy. There was dramatic clinical improvement over the next month. She became alert, fed herself, began to speak coherently, and walked with support for the first time in nine months: Her hair grew about one=half inch, the skin lesions resolved, and muscle tone increased markedly. Serum biotinidase activity was undetectable. Patient 6. Clinical and biochemical findings in this boy have been reported elsewhere. ~5 The parents were not consanguineous, and the infant was not breast-fed. Serum biotinidase activity was 0.18 nmol/min/ml.

RESULTS

AND

DISCUSSION

Five of o u r r e p o r t e d c h i l d r e n h a d d o c u m e n t e d biotinid a s e deficiency. P a t i e n t 1 w a s a s s u m e d to have h a d t h e s a m e d i s o r d e r as h e r siblings. All of t h e s e individuals exhibited s o m e or all o f t h e

s y m p t o m s u s u a l l y seen in

p a t i e n t s with late-onset M C D . I n t w o ( p a t i e n t s 4 a n d 5) M C D w a s d i a g n o s e d b e c a u s e t h e y h a d o r g a n i c a c i d u r i a in addition to t h e n e u r o l o g i c a n d c u t a n e o u s f e a t u r e s c h a r a c teristic of t h e late-onset disorder. T h e r e m a i n i n g p a t i e n t s h a d either t h e neurologic or c u t a n e o u s f e a t u r e s or both, w h i c h are c h a r a c t e r i s t i c o f l a t e - o n s e t M C D , b u t have not exhibited m e t a b o l i c acidosis or o r g a n i c aciduria. I n previously r e p o r t e d cases, t h e diagnosis o f late-onset M C D was not m a d e in the a b s e n c e o f d o c u m e n t e d o r g a n i c aciduria, a Criterion t h a t w o u l d h a v e excluded f o u r of o u r p a t i e n t s with biotinidase deficiency ( T a b l e ) . N o t only is t h e r e clinical variability a m o n g p a t i e n t s f r o m different families, b u t t h e r e is v a r i a b i l i t y in e x p r e s s i o n of the d i s o r d e r a m o n g f a m i l y m e m b e r s ( p a t i e n t s 1, 2, a n d 3).

236

W o l f et al.

In addition to being present in serum, biotinidase is present in the liver, intestines, and kidney. 8 The enzyme permits the recycling of biotin for reutilization in the activation of apocarboxyalses to active holocarboxylases?6 Individuals with biotinidase deficiency are unable to recycle their endogenous biotin stores and to degrade completely the biotin-dependent carboxylases. This may result in the formation and accumulation of biocytin, which cannot be further degraded. Therefore, if the dietary intake of biotin fails to replenish the amount normally recycled by the biotinidase salvage pathway, a biotindeficiency state will gradually develop. In pharmacologic doses, exogenous biotin can replace the amount of the vitamin normally derived from the recycling of endogenous biocytin. Although the biochemical abnormalities attributed to MCD are often life threatening, they appear to represent a relatively late effect of biotinidase deficiency. The cutaneous symptoms and some of the neurologic signs are quite reminiscent of findings noted in experimental biotin deftciency ~72~ and usually occur earlier in the course of the disease. It seems likely that the cutaneous and neurologic symptoms of biotinidase deficiency result from mild to moderate depletion of biotin at a time when the residual carboxylase activities are still adequate to maintain normal metabolic balance. Ketoacidosis and organic aciduria appear only after protracted biotin deficiency. It is also possible that biocytin, a metabolite that may never accumulate to any appreciable degree in normal individuals, has a direct or synergistic toxic effect on the disease process, possibly by acting as a competitive inhibitor of biotin or by some other mechanisms. This seems a less likely possibility, because most, if not all, of the symptoms disappear after the administration of high doses of biotin, a treatment that should not affect the accumulation of biocytin. Cutaneous and neurologic symptoms are not a feature of holocarboxylase synthetase deficiency; therefore, they could represent a manifestation of biotin deficiency or of biocytin toxicity. Differences in the dietary intake of biotin or avidin, intestinal absorption of biotin, or differences in the quantity of biotin produced by the intestinal flora may contribute to the high degree of clinical variability seen in biotinidase deficiency. For example, human milk usually contains less biotin than is present in formula preparations, which are supplemented with biotin. Therefore, breast-fed babies with biotinidase deficiency may become symptomatic earlier than those fed formula. The serum biotin concentrations of our patients and others reported with late-onset MCD have been normal or below the normal range prior to biotin treatment? .2 Because most methods used to determine biotin quantita-

The Journal of Pediatrics August 1983

tively measure both biotin and biocytinfl2' 23 it is possible that the reported serum biotin concentrations may be spuriously high, reflecting in part an elevation in serum biocytin. Our attempts at measuring biocytin in the serum or urine by column chromatographic methods have been unsuccessful. However, this is understandable, because even if all the measured "biotin" in serum is biocytin, the most sensitive amino acid analyses will not detect it. Several studies have been reported in which the increase in serum concentration of biotin after the administration of varying quantities of oral biotin to patients with late-onset MCD has been interpreted as indicating an abnormality in the intestinal absorption of biotin. 24'25 Other reports have described abnormal urinary excretion of biotin in patients with late-onset MCDfl 6 A possible explanation is that the tissue concentrations of free biotin in these patients are comparable to that in a biotin-deficient individual. When biotinidase-deficient patients are administered varying concentrations of biotin orally the vitamin is rapidly taken up by the tissues, resulting in lower than normally expected plasma biotin concentrations. This would, therefore, be perceived as decreased intestinal absorption of biotin. In addition, in vitro studies of intestinal biotin uptake in hamsters have demonstrated that biocytin is a potent competitive inhibitor of biotin absorption, 27 and it seems possible that the apparent defect in renal and intestinal transport may reflect a competitive inhibition by endogenous biocytin in affected subjects. In patients with biotinidase deficiency with a normal dietary biotin intake, the ratio of biocytin to biotin may gradually increase to a critical level at which biocytin can competitively inhibit these various transport pathways. Moreover, biocytin in the tissues may be less readily transported into the serum, compared with free biotin, thereby resulting in a net decrease in serum "biotin" concentrations. It is possible that biocytin is accumulating in the tissues, much like the degraded metabolites formed in storage diseases. Our findings suggest that even in the absence of metabolic acidosis or organic aciduria, infants or children exhibiting either neurologic symptoms, such as seizures or ataxia, or cutaneous features, such as skin rash, alopecia, or candidiasis, alone or in combination, should be given a trial of a pharmacologic dose of biotin (at least 10 mg daily). If the symptoms improve after biotin administration, biotinidase deficiency should b e considered, and the diagnosis can be confirmed by measuring the serum biotinidase activity. We have shown previously that the presence of high concentrations of biotin in the serum at the time of assay does not interfere with the enzyme activity determination. 5'6 Biotinidase deficiency thus joins pyridoxine-responsive seizures as a specific and treatable form of infantile seizures.

Volume 103 Number 2

We thank Dr. Walter E. Nance for invaluable discussions and suggestions, Drs. H. Baker and K. Bartlett for performing the biotin determinations, and Terry Mayo for excellent secretarial assistance. REFERENCES 1. Sweetman L: Two forms of biotin responsive multiple carboxylase deficiency. J Inherited Metab Dis 4:53, 1981. 2. Wolf B, Feldman GL: The biotin-dependent carboxylase deficiencies. Am J Hum Genet 34:699, 1982. 3. Burri BJ, Sweetman L, Nyhan WL: Mutant holocarboxylase synthetase: Evidence for the enzyme defect in early infantile biotin-responsive multiple carboxylase deficiency. J Clin Invest 68:1491, 1981. 4. Saunders ME, Sherwood WG, Duthie L, Surh L, Gravel RA: Evidence for a defect of holocarboxylase synthetase activity in cultured lymphoblasts from a patient with biotin-responsive multiple carboxylase deficiency. Am J Hum Genet 34:590, 1982. 5. Wolf B, Grier RE, Parker WD, Goodman SI, Allen R J: Deficient biotinidase in late-onset multiple carboxylase deficiency. N Engl J Med 308:161, 1983. 6. Wolf B, Grier RE, Allen R J, Goodman SI, Kien CL: Biotinidase deficiency: The enzymatic defect in late-onset multiple carboxylase deficiency. Clin Chim Acta (In press.) 7. Wright LD, Driscoll CA, Boger WP: Biocytinase, an enzyme concerned with hydrolytic cleavage of biocytin. Proe Soc Exp Biol Med 86:335, 1954. 8. Koivusalo M, Pispa J: Biotinidase activity in animal tissue. Acta Physiol Scand 58:13, 1963. 9. Goodman SI, Markey, SP: Diagnosis of organic acidemias by gas chromatography mass spectroscopy. In New York, 1981, Alan R. Liss, pp 105-114. 10. Wolf B, Hsia YE, Rosenberg LE: Biochemcal differences between mutant propionyl CoA carboxylases from two complementation groups. Am J Hum Genet 29:378, 1977. 11. Wolf B, Rosenberg LE: Heterozygote expression in propionyl CoA carboxylase deficiency: Differences between major complementation groups. J Clin Invest 62:931, 1978. 12. Feldman GL, Wolf B: Evidence of two genetic complementation groups in pyruvate carboxylase deficient human fibroblast cell lines. Biochem Genet 18:617, 1980. 13. Knappe J, Brommer W, Brederbick K: Reinigung und eigenschaften der biotinidase aus schweinenieren und Lactobacillus casei. Biochem 338"599, 1963. 14. Parker WD, Goodman SI, Stumpf DA, Wolf B: Biotinresponsive opsoclonus-myoclonus syndrome. Neurology (In press.) 15. Swick HM, Kien CL: Biotin deficiency with neurologic and cutaneous manifestations but without organic aciduria. J PEDIATR 103:265, 1983. 16. Moss J, Lane MD: The biotin-dependent enzymes. Adv Enzymol 35:321, 1971. 17. Achuta Murthy PN, Mistry SP: Biotin. Prog Fed Nutri Sci 2:405, 1977.

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18. Sweetman L, Surh L, Baker H, Peterson RM, Nyhan WL: Clinical and metabolic abnormalities in a boy with dietary deficiency of biotin. Pediatrics 68:553, 1981. 19. Kien CL, Kohler E, Goodman SI, Berlow S, Hong R, Horowitz SP, Baker H: Biotin-responsive in vivo carboxylase deficiency in two siblings with secretory diarrhea receiving total parenteral nutrition. J PEDIATR 99:546, 1981. 20. Mock DM, DeLorimer AA, Liebman WM, Sweetman L, Baker H: Biotin deficiency: An unusual complication of parenteral alimentation. N Engl J Med 304:820, 1981. 21. McClain CJ, Baker H, Onstad GR: Biotin deficiency in an adult during home parenteral nutrition. JAMA 24"/:3116, 1982. 22. Baker H, Frank O, Matovitch VB, Pasher I, Aaronson S, Hutner SH, Sobotka H: A new assay method for biotin in blood, serum, urine, and tissues. Anal Biochem 3:31, 1962. 23. Landman A: A sensitive assay for biotin analogs and biotin proteins. Int J Vit Nutr Res 46:310, 1976. 24. Munnich A, Saudubray JM, Carr6 G, Coud6 FX, Ogier H, Charpentier C, Fr6zal J: Defective biotin absorption in multiple carboxylase deficiency. Lancet 2:263, 1981. 25. Thoene JG, Lemons RM, Baker H: Impaired intestinal absorption of biotin in juvenile multiple carboxylase deficiency. N Engl J Med 308:639, 1983. 26. Baumgartner R, Suormala T, Wick H, Geisert J: Renal loss of biotin: A cause of biotin-responsive multiple carboxylase deficiency. Pediatr Res 16:41, 1982. 27. Spencer RP, Brody KR: Biotin transport by small intestine of rat, hamster, and other species. Am J Physiol 206:653, 1964. 28. Thoene J, Baker H, Yoshino M, Sweetman L: Biotinresponsive carboxylase deficiency associated with subnormal plasma and urinary biotin. N Engl J Med 304:817, 1981. 29. Charles BM, Hosking G, Green A, Pollitt R, Bartlett K, Taitz LS: Biotin-responsive alopecia and developmental regression. Lancet 2:118, 1979. 30. Bartlett K, Helen NG, Leonard JV: A combined defect of three mitochondrial carboxylases presenting as biotin-responsive 3-methylcrotonyl glycinuria and 3-hydroxyisovaleric aciduria. Clin Chim Acta 100:183, 1980. 31. Leonard JV, Seakins JWT, Bartlett K, Hyde J, Wilson J, Clayton B: Inherited disorders of 3-methylcrotonyl CoA carboxylation. 56:53, 1982. 32. Keeton BR, Moosa: Organic aciduria: Treatable cause of floppy infant syndrome. Arch Dis Child 51:636, 1976. 33. Cowan M J, Packman S, Wara DW, Ammann A J: Multiple biotin-dependent carboxylase deficiencies associated with defects in T-cell and B-cell immunity. Lancet 2:115, 1979. 34. Lehnert W, Niederhoff H, Junker A, Saule H, Frasch W: A case of biotin-responsive 3-methylcrotonylglycin- and 3-hydroxyisovaleric aciduria. Eur J Pediatr 132:107, 1979. 35. Munnich A, Saudubray JM, Cotisson A, Coude FX, Ogler H, Charpentier C, Marsac C, Carre G, Bourgeay-Causse M, Fr6zal J: Biotin dependent multiple carboxylase deficiency presenting as a congenital lactic acidosis. Eur J Pediatr 137:203, 1981.